The inventive concepts relate to image sensors and methods of manufacturing the same.
Image sensors may be classified into charge-coupled device (CCD) type image sensors and complementary metal-oxide-semiconductor (CMOS) type image sensors (CIS). The CIS may include a plurality of two-dimensionally arranged pixels. Each of the pixels may include a photodiode (PD) that coverts incident light into an electrical signal.
As semiconductor devices have been more highly integrated, the image sensors have also been more highly integrated. The sizes of the pixels have also been reduced by the high integration of the image sensors, so the reliability of the image sensors may deteriorate due to a cross-talk between pixels.
A P+ accumulation layer may be formed in an upper portion of a photodiode using an ion implantation process to suppress a dark current caused by traps between the photodiode and an anti-reflection layer. Trap assisted electrons may be recombined with holes existing in the P+ accumulation layer, thereby suppressing the dark current.
The surface of a silicon substrate may be damaged by the ion implantation process, which may produce further trap sites on the surface of the silicon substrate. In addition, a high-temperature process should be performed in order to activate P-type dopants implanted in the P+ accumulation layer.